I also like this scene because of what it tells us about Bingley. First off, his attentions to Jane are becoming quite clear:

On distinguishing the ladies of the group the two gentlemen came directly towards them, and began the usual civilities. Bingley was the principal spokesman, and Miss Bennet the principal object. He was then, he said, on his way to Longbourn on purpose to inquire after her.

Bingley and Darcy are riding through Meryton on their way to Longbourn (btw -- Darcy going to Longbourn, oh my!). Bingley wanted to make a special visit to see if Jane were well, and I think this speaks volumes about both his consideration of other people in general and his feelings for Jane specifically.

Secondly, this little throw-away line about Bingley:

In another minute Mr. Bingley, but without seeming to have noticed what passed, took leave and rode on with his friend.

I take this to mean that Bingley did notice that Darcy was upset (though he may not have known the reason), and that he chose to end his conversation with Jane in order to alleviate his friend's distress.